Manufacture of nitric acid.



MfMoBsT a.; R. M. von BBRNECK.

vmmUrAo'rtrnE or N lmuo Aon I urLroATIoN FILED JULY ze, 191,1.

'NEOIQ chemist, citizens of the pure oxygen instead of lconverting theseUNITED sTATEs PATENT oEEIoE.

MARTIN MOEST .AND RUDOLF MLLER von BERNECK, or HoHsT-ON-THE-MAIN, GER-MANY, ASSIGNORS TO IIFARJBTIIRKE VORM. MEISTER LUCIUS @tA BRNING, 0F

GERMANY, A CORPORATION OF GERMANY. l

HOcHsT-ON-THE-MAIN,

MANUFACTURE 0F N ITRIC ACID.

spevcineation of Letters Patent. Application led July 26,

Patented Jan. 7, 19113.

1911. Serial No. 640,654.

To all z vzom-z't may concern.'

Be it known that we, MARTIN MOEST, Ph. D., chemist, and RUDOLF MLLERVONBER- Empire of Germany, residing at Hchst-on-the-Main', Germany, haveinvented certain new and useful Improvements in t-he Manufacture ofNitric Acid, of which the following is a specification.

In the manufacture of concentrated nitric oXid gases, which can nowV beobtained in a simple and cheap way (see German Patent No. 220539 andGerman patent application F. 31241), it is advantageous to useatmospheric air for gases into nitric acid in presence of water oraqueous solutions, because a nitric acid of a higher concentration isthereby obtained and also-the absorption compartments can be smaller. Inthat process there are generally used for conveying the liquid into theabsorption-vessels, apparatus which are worked by compressed air, forinstance acid pulsometers, montejus, or any other similar automaticapparatus. The escaping. airis either allowed to escape into the openair, in which case very considerable losses of nitric oXid gases andnitric acid respectively occur, or the escaping airis introduced intothe absorption-system. Although in the latter case n stead of acldvapors which If one is compelled, as

direct losses of nitric acid are avoided, there is the disadvantage'thatnitrogen gets into the absorption-system and dilutesthe gases.

it frequently happens in practice, to repeatedly conduct the liquidthrough the absorption-system, the dilution of the gases by the oxygenintroduced may be-so much increased that the advantage in using pureoxygen is frustrated. 'Now we have found that these drawbacks can beobviated by using compressed oxygen in'- compressed air for theconveyance of the absorption liquid, and by reintroducing into theabsorption system, simultaneously with the nitric oxid gases or nitricmay be drawn along, theoxygen leaving the pressure-vessels. Byproceeding in this way,` not only losses of nitrogen, but also dilutionof the nitric oxid gases in the absorption-systems are avoided. As theoxygen leaving the pressure-'apparatus enters again theabsorptionsystem, no additional consumption of Oxyverted into nitricyacid with the aid of water l and oxygen, are connected with each otherby the gas-pipes G, and water is introduced into the chamber T4, atHgO;oXids of nitrogen at NO2; and oxygen at O. The gases pass' through. thesystem in the direction inwhereas the water and the nitric acid vflow inthe opposite direction, from the bottom of one chamber, through thelifting apparatus, into Athe top of the next chamber.

D1, D., and D, indicate the apparatus for lifting the nitric acidproduced, with the aid of oxygen. The oxygen, after having dicated bvvthe arrows-adjacent to pipes G,

been used for transporting the nitric acid,-

is collected by a common conduit A, and is introduced at a suitable]point into the system, where it is used for the formation of nitric acidwith oxidation of the oxids of nitrogen. The finished product is drawnoft' from chamber T1 at B.

It is to be understood that the expression in presence of water,occurring in the claim, is a general one, and is intended to includeaqueous solutions as well.

Having now described Vour invention, what weclaim is:

In the process of manufacturing nitric acid from nitric oXids and oxygenin presence of water, the steps \which consist in charging with oxygenthe apparatus serving for the conveyance ofthe liquid in the ab-Osorption-systems, and in re-introducing into the absorption-system theoxygen leaving the apparatus, simultaneously with the entrained vaporscontaining nitric acid.

In testimony whereof, we atlix our signatures in lpresence of twowitnesses.

MARTIN MOEST. v RUDOLEMLLER VON BERNECK. Witnesses:

JEAN GRUND,

CARL GRUND.

